Stripping composition and method for stripping a road or highway surface

ABSTRACT

The disclosed striping composition provides a fast cure on road or highway surfaces. The striping composition is a two-part (part A and part B) polyurethane forming system having good adhesion characteristics to a road or highway surface, and weathering and yellowing resistance over time. Part A contains an aliphatic polyol and part B contains an aliphatic polyisocyanate.

FIELD OF THE INVENTION

This invention relates to a striping composition for use on a road orhighway surface, a method for striping or marking a road or highwaysurface, and the resulting striped or marked road or highway. Thestriping composition is a two-part polyurethane forming system havingfast cure properties; good adhesion characteristics to a road or highwaysurface; good weathering and abrasion resistance; and amberingresistance over time.

BACKGROUND OF THE INVENTION

Various striping or marking compositions have been used on roads andhighways for many years. The first class of striping compositions usedon roads and highways with some success were alkyd-based paintcompositions such as those disclosed in U.S. Pat. Nos. 2,897,732;2,897,733; and 3,326,098. Alkyd-based paint compositions are generallyslow to dry and contain ester linkages which are susceptible tohydrolysis from the alkaline condition of roads. This hydrolysis, inpart, causes the applied paint to have poor wear resistance.Accordingly, it is desireable to provide a striping composition having amuch faster cure time and improved wear resistance.

Most alkyd-based paint compositions require the addition of a solvent ordrying oil to decrease the viscosity so that the paint composition canbe sprayed onto road surfaces. For example, see U.S. Pat. No. 3,326,098.The presence of a solvent during highway marking creates a pollutionproblem since the solvent evaporates into the atmosphere. Accordingly,it is desireable to provide a striping composition which is 100% solids,and does not contain solvents or drying oils.

As an alternative to alkyd-based paint compositions, solvent freeepoxy-based striping compositions were developed. Epoxy-based stripingcompositions are described in detail in U.S. Pat. Nos. 4,088,633;4,185,132; and 4,255,468. These striping compositions are a significantimprovement over prior alkyd-based paints in terms of alkaline and wearresistance, and in reducing the need for solvents during application. Inparticular, the epoxy-based striping compositions are better atwithstanding water immersion compared with the alkyds. In addition, theyprovide a better bond to glass beads dropped thereon which is importantfor providing retroreflectivity at night. Increased adhesion to glassbeads provides better retention of the glass beads to the road surfacefor a longer period of time. Epoxy-based striping compositions, however,are still generally too slow in curing, particularly on a cold roadsurface. In addition, they age harden and become brittle, and have atendency to amber. As a result of the slow curing rate for suchepoxy-based striping compositions, it is necessary to put cones alongthe striping composition applied to a road surface to prevent carstraveling along the road from tracking the uncured composition. Thenecessity for coning while the epoxy-based striping composition curesincreases the cost of striping a road by requiring a number of conessufficient to prevent cars and trucks from tracking the stripingcomposition before it cures, and by providing the necessity foremploying crews to put the cones down once the striping composition isapplied and to pick the cones up once it cures. Accordingly, it would bedesirable to stripe a road with a composition that is fast cure, even oncold road surfaces, in order to eliminate the need for coning andthereby enhance striping efficiency.

Furthermore, it would be desireable to provide a fast cure stripingcomposition having good adhesion characteristics to road or highwaysurfaces and which can withstand weathering and which will notsignificantly amber over time.

SUMMARY OF THE INVENTION

A striping composition for use on a road or highway surface, a methodfor striping a road or highway surface, and a striped road or highwaysurface are provided by the present invention. The striping compositionhas fast cure properties, has good adhesion characteristics to a road orhighway surface; good weathering and abrasion resistance; and amberingresistance over time.

The striping composition for use on a road or highway surface accordingto the present invention is prepared from a two-part polyurethaneforming system containing a first part (part A) and a second part (partB). Part A contains an isocyanate-reactive group-containing componentand part B contains an isocyanate group-containing component. Parts Aand B react to form a polyurethane system.

Part A of the polyurethane forming system can contain any polyol capableof reacting with the polyisocyanate in part B. The polyol component isselected based upon the desired properties of the final polyurethanecomposition, which include adhesiveness, amber resistance, strength andflexibility, and upon the desired properties of part A, which includeviscosity and reactivity. In order to provide these properties, thepolyol component can be a mixture of polyols. Polyols useful in part Apreferably include compounds and polymers which are diols, triols, andtetraols. The hydroxyl groups can be primary, secondary or tertiary.

The polyol compounds and polymers can be glycols, alkane polyols whichare lower (C₁ -C₁₀) or higher (C₁ -C₃₀), polyether polyols, epoxyresins, and monosaccharides. Preferably, part A contains a mixture ofpolyols such as, for example, a mixture of a secondary diether diol anda lower polyalkylene glycol. Preferably, the secondary diether diol isthe diether of propylene glycol and bisphenol A, and the lowerpolyalkylene glycol is tripropylene glycol.

Part B of the polyurethane system can be any polyisocyanate capable ofreacting with the polyol in part A to provide a fast cure stripingcomposition having a desirable degree of adhesion to a road or highwaysurface, strength and flexibility, and amber resistance over time, andwhich will provide a part B having a desired degree of reactivity and aviscosity sufficient for processing in commercial striping or markingmachinery without the use of solvents. Mixtures of polyisocyanates canbe used. Aliphatic and cycloaliphatic polyisocyanate are desirablebecause they tend to produce polyurethanes having decreased ambering.Trimerized hexamethylene diisocyanate (HDI), a trifunctionalisocyanurate, is a preferred aliphatic polyisocyanate. In order toincrease the reactivity and decrease the viscosity of part B, andprovide a harder polyurethane, any colorless or lightly colored aromaticpolyisocyanates can be used in combination with the aliphatic orcycloaliphatic polyisocyanate. Diphenyl methane diisocyanate (e.g.,diphenyl methane-2,4'- and/or -4,4'-diisocyanate) is a preferredaromatic polyisocyanate because it is very lightly colored. Thisaromatic polyisocyanate component is particularly advantageous when itis combined with trimerized hexamethylene diisocyanate.

Generally, if the striping composition is uncured, either parts A and Bhave not been combined or parts A and B have been combined but thecombination has not resulted in a cured polyurethane system. While thestriping composition is uncured, reflectorizing filler can be addedthereto to provide a cured striping composition having desiredretroreflectivity.

The present invention provides a method for striping a road or highwaysurface which involves combining part A containing isocyanate-reactivegroup-containing components and part B containing isocyanategroup-containing components to form a reacting striping composition,applying the reacting striping composition to a road or highway surface,and allowing the reacting striping composition to cure and adhere to theroad or highway surface. If desired, reflectorizing filler can be addedto the reacting striping composition to provide a striped road orhighway surface having retroreflectivity effect.

Parts A and B can be applied to a road or highway surface using anapplicator which can be a commercially available striping or markingapparatus to form a film on the road or highway surface. Generally, thefilm will have a thickness of about 4 mm to about 20 mm depending onwhether reflectorizing filler is incorporated therein.

DETAILED DESCRIPTION OF THE INVENTION

The striping composition of the invention can be 100% solids. The term"solids" in this context is borrowed from paint chemistry, wherein"solids" includes any components (be they liquid or solid) which becomesa part of the ultimately obtained solid coating. That is, the term"solids" excludes essentially volatile solvents or carriers. The phrase"essentially volatile" is meant to include a liquid which has a boilingpoint or initial boiling point below 150° C. at normal atmosphericpressure.

The striping composition can have fast cure properties. The phrase "fastcure" has been used in the prior art to describe a striping compositionhaving a "no track time" of about 5-10 minutes at room temperature. SeeU.S. Pat. No. 4,255,468. As used herein, the phrase "fast cure" isintended to describe a striping composition which achieves a "no tracktime" in at least about four minutes at room temperature. The "notracking time" is defined as the amount of time necessary for thestriping composition, once applied to a road or highway surface, to cureto an extent sufficient to resist tracking by standard automobile andtruck traffic. Preferably, the no track time is an amount of timesufficient to eliminate the need for coning to prevent tracking withoutsignificantly disrupting regular traffic patterns. More preferably, theno track time is less than 2 minutes, even more preferably 10 seconds toabout 50 seconds, and most preferably, about 20 seconds to about 40seconds at 75° F.

It is desireable for the striping composition to be relatively "notrack." "Instant no track" may be possible from an application andcuring standpoint but it is usually desirable to have an "open time" toboth wet the surface of the road or highway and to receive the glassbeads. If the curing polymerization is too rapid, the resulting stripingcomposition has too much cohesion and not enough adhesion to the road orhighway surface. Although it is desireable to decrease no track time, itshould not be so short as to seriously sacrifice adhesion to a road orhighway surface. For most applications, a no track time of 20 or 30seconds is sufficient to provide adequate adhesion at room temperature(75° F.). On cold surfaces, it may be desirable to provide a longer notrack time in order to provide sufficient adhesion to the road orhighway surface. While providing fast cure properties, the stripingcomposition of the present invention adheres sufficiently well to a roador highway surface so that it has a long life expectancy and can resistpeeling or abrasion caused by traffic including snow plows.

The striping composition can be applied to any type of road surface.Preferably, the road surface is made of asphalt or concrete upon whichthe striping composition of the present invention adheres very wellsince it is porous. Although the striping composition adheres well tomost road or highway surfaces, it can adhere slightly to other lessporous surfaces such as metal. This property helps prevent the stripingcomposition from adhering to the applicator. If desired, the stripingcomposition can be applied to a porous road surface with as much forceas desired to ensure sufficient adhesion thereto.

Part A System

This invention contemplates the use of an isocyanate-reactivegroup-containing component (part A) capable of reacting with theisocyanate group-containing component contained in part B to provide afast cure striping composition. The isocyanate-reactive group-containingcomponent preferably contains polyols or thiols. The polyol component isselected based upon the desired properties of the final polyurethanecomposition, which include adhesiveness, amber resistance strength andflexibility, and upon the desired properties of part A, which includeviscosity and reactivity. In order to provide these properties, thepolyol component can be a mixture of polyols. Exemplary polyols whichcan be used to form non-yellowing or non-ambering polyurethanes aregenerally described in U.S. Pat. Nos. 4,604,418 and 5,159,045, which areincorporated herein by reference. These polyols include compounds andpolymers which are diols, triols, and tetraols.

The compounds and polymers include, for example, glycols such asethylene Glycol, propylene Glycol, β,β'-dihydroxyethyl ether (diethyleneGlycol), dipropylene glycol, 1,4-butylene Glycol, 1,3-butylene Glycol,1,6-hexamethylene Glycol, neopentyl Glycol, polyethylene glycol,polypropylene Glycol, polypropylene-polyethylene glycol and polybutyleneGlycol; alkane polyols such as glycerol, trimethylolpropane,hexanetriol, pentaerythritol, xylitol and sorbitol; polyether polyolsobtained by addition polymerization of a single compound or a mixture ofalkylene oxide such as ethylene oxide, propylene oxide and 1,2-butyleneoxide to a single compound or a mixture of polyhydric alcohols such asglycerol and propylene Glycol or polyfunctional compounds such asethylene diamine and ethanolamine; epoxy resins of novolak type,β-methylepichloro type, cyclooxirane type, glycidyl ether type, glycidylester type, Glycol ether type, epoxylated unsaturated fatty acid type,epoxylated fatty acid ester type, polybasic carboxylic acid ester type,amino-glycidyl type, halogenated type and resorcinol type; andmonosaccharides or derivatives thereof selected from fructose, glucose,saccharose, lactose or 2-methylglucoxide.

For most applications, however, polyols containing ester groups are notpreferred because they tend to hydrolyze in the presence of alkalinepresent on road surfaces. Unsaturation also tends to hydrolize in thepresence of alkaline. If desired, polyesters and polyacrylates or otherunsaturated polymers can be used. Such polymers are well known in theart.

Part A preferably contains a mixture of a secondary diether diol and alower polyalkylene glycol component. A lower polyalkylene glycol ismeant to include polymers of glycols wherein the glycols have 2-10carbon atoms. The secondary diether diol provides the backbone for thestriping composition and is preferably a diether of propylene glycol andbisphenol A which is commercially available under the trademark DOWRESIN 565, a product of Dow Chemical Co. The lower polyalkylene glycolis preferably tripropylene glycol. The secondary diether diol ispreferably present in an amount ranging from about 30-90% by weightbased on the total reactant weight in part A, and more preferably about50-80% by weight. At greater amounts of this component, the stripingcomposition becomes too soft. The lower alkylene glycol can be presentin an amount ranging from 10-70% by weight based on the total reactantweight in part A, and more preferably about 20-40% by weight. At greateramounts of this component, the striping composition becomes too brittle.

The Part B System

This invention contemplates the use of an isocyanate group-containingcomponent (part B) capable of reacting with the isocyanate-reactivegroup-containing components contained in part A to provide a fast curestriping composition. The isocyanate group-containing component (part B)preferably contains polyisocyanates having a sufficient viscosity whichwill allow part B to be processed through road striping apparatuswithout the use of solvents. The polyisocyanates should be capable ofreacting with the polyols in part A to form a polyurethane system whichwill not significantly amber over time.

Aliphatic and cycloaliphatic polyisocyanate are preferably used in partB because they tend to produce polyurethanes having decreased ambering.Generally, aliphatic and cycloaliphatic polyisocyanates which can beused in the present invention correspond to the formula

    Q(NCO).sub.n

in which n is an integer 2 to 4, and Q represents an aliphatichydrocarbon radical containing from 2 to 100 carbon atoms, and zero to50 heteroatoms, or a cycloaliphatic hydrocarbon radical containing from4 to 100 carbon atoms and zero to 50 heteroatoms. Examples of aliphaticand cycloaliphatic polyisocyanates include ethylene diisocyanate,1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate,trimethylhexamethylene diisocyanate, 1,12-dodecane diisocyanate,cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate andmixture of those isomers, and1-isocyanate-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane. Preferredaliphatic and cycloaliphatic polyisocyanates are hexamethylenediisocyanate, its isocyanurate and its biuret and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophoronediisocyanate). More preferably, the polyisocyanate is trimerizedhexamethylene diisocyanate (HDI), a trifunctional isocyanurate. Acommercially available trimerized hexamethylene diisocyanate is soldunder the trademark DESMODUR N-3300 by Miles, Inc.

The use of aliphatic or cycloaliphatic polyisocyanates as the onlyisocyanate group-containing components in part B can produce a systemhaving a viscosity which is too high for convenient use in commercialroad striping equipment. According to the present invention, it ispossible to replace part of the aliphatic or cycloaliphaticpolyisocyanate with an aromatic polyisocyanate. Aromatic polyisocyanatescan be useful because they tend to have a viscosity decreasing effectwhen mixed with aliphatic or cycloaliphatic polyisocyanates and becausethey tend to react quickly. In addition, aromatic polyisocyanates tendto provide a faster reaction time and a harder finish. Aliphaticisocyanates tend to a produce softer polyurethane but are more lightstable. Unfortunately, most aromatic polyisocyanates are brown and tendto produce yellow or brown polyurethanes. However, by using an aromaticpolyisocyanate which is colorless or only very slightly colored, it ispossible to produce a polyurethane which retains good amber resistantproperties. One skilled in the art will readily appreciate that thearomatic polyisocyanate should be present in an amount sufficient todecrease the viscosity of part B so it can be processed through roadstriping equipment but within a range sufficient to prevent significantyellowing or ambering of the resulting polyurethane.

Diphenyl methane diisocyanate (e.g., diphenyl methane-2,4'- and/or-4,4'-diisocyanate) is a preferred aromatic polyisocyanate because it isvery lightly colored. This aromatic polyisocyanate component isparticularly advantageous because when it is combined with trimerizedhexamethylene diisocyanate, a polyurethane resin can be produced whichdoes not significantly amber. Diphenyl methane diisocyanate iscommercially available under the trademark LUPRANATE MP-102 sold by BASFCorporation. Other colorless or lightly colored aromatic polyisocyanatescan similarly be used. Aromatic polyisocyanates which might be colorlessand, therefore, useful in the present invention include 2,4- and2,6-hexahydrotolylene diisocyanate, hexahydro-1,3- and/or -4,4'-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and2,6-tolylene diisocyanate, and naphthalene-1,5-diisocyanate.

The aliphatic polyisocyanate should be present in an amount of about50-100% by weight based on the total weight of polyisocyantes in part B.Preferably, the aliphatic polyisocyanate is present in an amount ofabout 40-90% by weight, and more preferably 70-80% by weight. Thearomatic polyisocyanate should be present in an amount of about 0-50% byweight based on the total weight of polyisocyanates in part B.Preferably, the aromatic polyisocyanate is present in an amount of about5.0-40% by weight, and more preferably 10-20% by weight.

Part A and/or Part B can contain a catalyst or a mixture of catalystscapable of accelerating the cure rate of the polyurethane formingsystem. Desirably, the two-part polyurethane forming system cures insufficient time to be considered a fast cure polyurethane. Any catalystcapable of accelerating the reaction rate between isocyanates andalcohols can be used in the present invention. Preferably, the catalystis capable of accelerating the reaction between aliphatic and/orcycloaliphatic polyisocyanates and polyols. Exemplary catalysts aredescribed in Squiller et al., "Catalysis In Aliphatic Isocyanate-AlcoholReactions," Modern Paint And Coatings, June 1987. Such catalysts includestannous octoate, dibutyltin dilaurate, manganese octoate, zirconiumoctoate, cobalt octoate, lead octoate, bismuth stannate, lead stannate,zirconium octoate, zinc octoate, dibutyltin bis-O-phenylphenate,dibutyltin S,S-dibutyldithiocarbonate, triphenylantimony dichloride,dibutyltin maleate, stannous oxalate, stannous stearate, barium nitrate,cadmium octoate, dibutyltin diacetate, dibutyltin dilauryl mercaptide,DABCO catalyst, DBTDL and DABCO catalyst, bismuth stearate, leadstearate, dimethyltin dichloride, stannous napthenate and mixturesthereof. Dibutyltin dilaurate is a particularly preferred catalyst foruse in the present invention because of its reliability for catalyzingpolyurethanes.

The catalyst component is preferably incorporated into part A since thepolyols are relatively unreactive until mixed with the polyisocyanate.The catalyst could be incorporated into part B but may have a tendencyto accelerate the reaction between the isocyanate groups and atmosphericor trace water. Generally, the catalyst is incorporated into part Aand/or part B in an amount sufficient to provide desired catalyticactivity. One skilled in the art would readily appreciate the amount ofcatalyst necessary to provide catalytic activity. Generally, thecatalyst should be present in an amount ranging from 0.1-10% by weightbased on the total weight of the reacting components.

A high pressure pump lubricant can additionally be incorporated intopart A and/or part B. Any known pump lubricant can be used, includingphosphates. A particularly preferred lubricant is tricresyl phosphatesold under the tradename KRONITEX TCP by FLM Corp. Surprisingly, whenthis pump lubricant is incorporated into part B, it additionally acts asan anti-moisture agent thereby extending the pot life of part B.Although not intending to be bound by theory, it is believed that thevapor pressure of this agent creates a gas barrier over thepolyisocyanates in part B thereby retarding access thereto byatmospheric moisture. Certainly, other pot life extending agents can beincorporated therein. Generally, the lubricant should be present in anamount ranging from about 0.1-5.0% by weight based on the total weightof the polyisocyantes in part B.

A heat dissipating additive can additionally be incorporated into part Aand/or part B. Usually, it is easier to incorporate it into part A sincepart A is more stable. The heat dissipating additive can be any inertdiluent. When used in part A, it can additionally provide compatibilitybetween the polyol components. Preferably, the heat dissipating agent isa chlorinated aliphatic hydrocarbon resin such as, for example,CHLOROWAX 50 (chlorinated paraffinic plasticizer, chlorine content 48wt. %, molecular weight 635), CHLOROWAX 60-70 (chlorinated paraffinicplasticizer, chlorine content 60 wt. %), and CHLOROWAX LV (paraffinicplasticizer, chlorine content 39 wt. %, molecular weight 545).Generally, the heat dissipating additive should be present in an amountranging from about 1.0-20.0% by weight based on the total weight of thereacting components in the striping composition.

It is preferred for traffic-marking purposes (particularly highwaymarking) that striping compositions of this invention either contain orbe combined with a reflectorizing filler such as glass or plastic beadsor bubbles. The reflectorizing filler is used to provide increaseretroreflectivity, particularly at night. The preferred reflectorizingadditive are smooth, round, transparent glass spheres (e.g. beads),substantially free of milkiness, film scratch, pits, and air bubbles.Preferably, not more than 30% of the beads are ovate or imperfect.

It presently appears that the most effective application of thereflectorizing filler is to treat it as a third part (part C) which canbe added to the part A/part B system before or after it has been appliedto a road or highway surface. Generally, the reflectorizing filler isdropped onto the applied striping composition and become embeddedtherein. Accordingly, it is desireable for the striping composition tohave an open time sufficient to receive the reflectorizing filler. Aless effective manner of incorporating the reflectorizing filler intothe part A/part B system is to mix them into the part A/part B mixturebefore it is applied to the road or highway surface. This latterapproach is particularly undesirable if the reflectorizing filler isbeads or bubbles which are easily fractured in a mixing step or ifmixing is otherwise made more complicated by, for example, abrading theapplication equipment. The amount of reflectorizing filler to beincorporated into the striping composition can easily be determined byone skilled in the art based upon the desired degree ofretroreflectivity and on the type of reflectorizing filler being used.Generally, the reflectorizing filler should be present in an amountranging from 10-98% by weight of the total weight of the stripingcomposition. Preferably, it is present in an amount ranging from 40-80%by weight of the total weight of the filler.

The two-part polyurethane forming system can contain additionalcomponents known in the art, if desired. Such additional componentsinclude, for example, diluents, pigments, plasticizers, leveling agents,surfactants, fillers, additives and the like. An exemplary pigmentincludes titanium dioxide which can be used as a whitener.

Formulation

Part A and part B are preferably combined prior to application to a roador highway surface. For example, parts A and B can be mixed in anycommercial in-line static mixer or auger which are well known in theart. It is believed Graco Inc. manufactures equipment which can processthe striping composition of the present invention. When applied to aroad or highway surface, the striping composition can be applied in anydesired thickness. The minimum thickness should be enough to provideadequate adhesion to the road or highway surface and sufficientvisibility. The maximum thickness is determined according to economicconsiderations taking into account the cost of the starting materialsand the potential increase in curing time to a thicker film to cure.Preferably, the film thickness is between about 1 to 100 mils (0.025-2.5mm) and more preferably 5-25 mils, depending upon the amount ofreflectorizing filler incorporated therein. Most commercial applicationwill provide a film thickness of about 10-15 mils.

The two-part striping composition preferably has a short pot life atroom temperature (75° F.). Preferably, the pot life is less than about 4minutes and more preferably less than about 1 minute. The pot life canbe reduced by incorporating a higher percentage of aromaticpolyisocyanate, using a different or greater amount of catalyst, heatingor combinations thereof. Certainly, the rate of reaction betweenpolyisocyanates and polyols additionally depends on the particularcomponents used in the reaction in terms of the reactivities of thecomponents, steric hinderance, etc., which would be understood by oneskilled in the art.

The striping composition can be applied at room temperature.Alternatively, one or both parts can be heated prior to use to providebetter flow properties and a faster cure time. Preferably, the two-partpolyurethane forming system is heated to a temperature in the range80°-200° F. prior to application. More preferably, it is heated to atemperature in the range of 100°-150° F.

The ratio of part A to part B is preferably near 1:1 by volume, forexample, between 0.97:1 and 1.05:1. One having skill in the art willreadily appreciate that the proportion of part A to part B can bealtered while staying within the spirit of the invention. It isdesireable to have a slight excess of isocyanate groups. An excess ofisocyanate groups of 1.05% is preferable in order to ensure that all ofthe hydroxyl groups of part A react. Excess isocyanate groups canusually react with water.

The resulting cured striping composition can be a thermoset and have ashore-D hardness of at least about 60, and more preferably at leastabout 75. The maximum shore-D hardness should be 100, and is preferablyless than 90. If the striping composition is too hard, it becomesbrittle. At lower harness levels, the striping composition will pick updirt to easily. Thus, the striping composition is advantageous becauseit resists dirt and retains flexibility. The striping composition shouldhave a high tensile strength and compression strength which allows it totake at least 10,000 psi. In addition, it should have sufficientabrasion resistance which allows it to withstand at least 1,000 cyclesfrom a CS 17 wheel Tabor abrader, and preferably at least 50,000 cycles.

The invention will be further described with reference to the followingspecific examples which are not intended to limit the scope ofinvention.

EXAMPLE 1

The following formulation in Table 1 illustrates a two-part polyurethaneforming system according to the present invention. Part A and part Bwere mixed together in a ratio of 1:1 by volume. The resulting mixturehad a pot life of approximately one minute at 75° F.

                  TABLE 1                                                         ______________________________________                                                        Parts by Weight                                               ______________________________________                                        Part A                                                                        DOW RESIN 565     70.0                                                        tripropylene glycol                                                                             30.0                                                        titanium dioxide  29.0                                                        CHLOROWAX LV      11.1                                                        dibutyltin dilaurate                                                                            04.0                                                        Part B                                                                        DESMODUR N-3300   114.0                                                       LUPRANATE MP102   36.0                                                        tricresyl phosphate                                                                             1.4                                                         ______________________________________                                    

The materials identified above by trademark have, according to theirsuppliers, the following chemical compositions.

"DOW RESIN 565": diether of propylene glycol and bisphenol A (thehydroxyl groups being secondary, available from Dow Chemical Company).

    ______________________________________                                        Property               Value                                                  ______________________________________                                        hydroxyl equivalent weight                                                                           175-185                                                viscosity (60° C.)                                                                            800-1700 cps                                           phenolic OH            0.02% max.                                             color, Gardner         5.0 max.                                               pounds/gallons (25° C.)                                                                       9.2                                                    density (80°/4° C.)                                                                    1.069                                                  ______________________________________                                    

"CHLOROWAX LV": liquid chlorinated paraffin, molecular weight 545.0(available from Occidental Chemical Corporation).

"DESMODUR N-3300": aliphatic polyisocyanate (available from Miles Inc.Coating Division).

"LUPRANATE MP102": 4,4' diphenyl methane diisocyanate (available fromBASF Corp. Polymers Division).

EXAMPLE 2

Part A and part B described in Example 1 were applied to a road surfaceby spray application in a ratio of 1:1 by volume. The resulting film waswhite and cured sufficiently quickly (i.e., about 30 seconds) so thatconing was not necessary. The cured striping composition adhered well toboth asphalt and concrete surfaces, and should have a shore-D hardnessin excess of 75 and not significantly yellow over time.

EXAMPLE 3

The process of example 1 was repeated and glass beads were dropped ontothe combined striping composition before it cured, and became imbeddedtherein. The striping composition would be very reflective at night. Thestriping composition adhered well to both asphalt and concrete surfaces.

EXAMPLE 4

A striping composition according to the present invention can beprepared having the formulation identified in Table 2, wherein parts Aand B can be mixed together in a ratio of 1.0:1.05 by volume.

                  TABLE 2                                                         ______________________________________                                                        Parts by Weight                                               ______________________________________                                        Part A                                                                        DOW RESIN 565     90.0                                                        tripropylene glycol                                                                             10.0                                                        titanium dioxide  29.0                                                        CHLOROWAX LV      11.1                                                        dibutyltin dilaurate                                                                            04.0                                                        Part B                                                                        DESMODUR N-3300   60.0                                                        LUPRANATE MP102   40.0                                                        tricresyl phosphate                                                                             1.4                                                         ______________________________________                                    

EXAMPLE 5

A striping composition according to the present invention can beprepared having the formulation identified in Table 3, wherein parts Aand B can be mixed together in a ratio of 0.97:1 by volume.

                  TABLE 3                                                         ______________________________________                                                        Parts by Weight                                               ______________________________________                                        Part A                                                                        DOW RESIN 565     30.0                                                        tripropylene glycol                                                                             70.0                                                        titanium dioxide  29.0                                                        CHLOROWAX LV      11.1                                                        dibutyltin dilaurate                                                                            04.0                                                        Part B                                                                        DESMODUR N-3300   90.0                                                        LUPRANATE MP102   10.0                                                        tricresyl phosphate                                                                             1.4                                                         ______________________________________                                    

It should be apparent to those skilled in the art that various changesmay be made to this invention without departing from the spirit thereof,and that the invention is not limited to what is described in thespecification but only as indicated in the appended claims.

I claim:
 1. A method for striping a road or highway surface, said methodcomprising the steps:(a) combining a first part containing isocyanatereactive group containing components and a second part containingisocyanate group containing components to form a reacting stripingcomposition free of essentially volatile solvents having a boiling pointbelow 150° C. at normal atmospheric pressure, (b) applying said reactingstriping composition to a road surface; (c) allowing said reactingstriping composition to cure and adhere to said road surface.
 2. Themethod according to claim 1, wherein said combining step involvesmixing.
 3. The method according to claim 1, wherein said combining stepinvolves spraying said first and second parts together.
 4. The methodaccording to claim 1, further comprising adding glass beads to saidreacting striping composition to provide a striped road surface havingretroreflectivity effect at night.
 5. The method according to claim 1,wherein said first part comprises a polyol selected from the groupconsisting of secondary diether polyols, alkylene glycols, polyalkyleneglycols and mixtures thereof.
 6. The method according to claim 1,wherein said second part comprises an aliphatic polyisocyanate and anaromatic polyisocyanate.
 7. The method according to claim 6, whereinsaid aliphatic polyisocyanate is trimerized hexamethylene diisocyanate.8. The method according to claim 6, wherein said aromatic polyisocyanateis diphenyl methane diisocyanate.
 9. The method according to claim 5,wherein said polyol is a mixture of a secondary diether diol andpolyalkylene glycol.
 10. The method according to claim 9, wherein saiddiether is a diether of propylene glycol and bisphenol A.
 11. The methodaccording to claim 5, wherein said polyalkylene glycol is tripropyleneglycol.
 12. The method according to claim 1, wherein said second partfurther comprises a non-reactive lubricant capable of extending the potlife thereof compared with a second part not containing saidnon-reactive lubricant.
 13. The method according to claim 1, whereinsaid first part further comprises a catalyst and a heat dissipatingadditive.
 14. The method according to claim 1, wherein said compositionwill cure within four minutes after combining said first part and saidsecond part, said cure takes place to an extent sufficient to preventtracking thereof by ordinary highway traffic.
 15. The method accordingto claim 14, wherein said composition will cure within one minute aftercombining said first part and said second part.
 16. The method accordingto claim 1, wherein said first part comprising:

    ______________________________________                                                          Parts by Weight                                             ______________________________________                                        diether of propylene glycol and                                                                   70.0                                                      bisphenol A                                                                   tripropylene glycol 30.0                                                      titanium dioxide    29.0                                                      paraffinic plasticizer                                                                            11.1                                                      dibutyltin dilaurate                                                                              04.0                                                      ______________________________________                                    

said second part comprising:

    ______________________________________                                                             Parts by Weight                                          ______________________________________                                        trimerized hexamethylene diisocyanate                                                                114.0                                                  diphenyl methane diisocyanate                                                                        36.0                                                   tricresyl phosphate    1.4                                                    ______________________________________                                    


17. The method according to claim 1, wherein said striping compositioncures and adheres to said road surface to provide a shore-D hardness ofbetween about 60 and about
 100. 18. The method according to claim 17,wherein the shore-D hardness is between about 75 and about 90.